@Anthony G Gordon, Sir, thank you very much for your valuable inputs.

Tinnitus is a noise, and you're aware that the noise is bothering you. Origin largely. Hallucinations are usually verbal (musical hallucinations are seemingly more rare), and the patient believes they are real. There also pseudo-hallucinations, where the patient has abnormal perception, but realises that his perception doesn't correspond to reality.

I'm not convinced that the continuum proposed by Anthony Gordon is logical in a linear fashion. My impression is that music-related and language-related perceptions occur with some degree of independence.

@Dirk Ulbricht sir, thank you for your wonderful explanation.

I agree with the colleagues above, hallucinations tend to be more constructed and cohesive ( i.e. voices, musical pieces etc), where as tinnitus is perceived as a specific frequency interference (I wouldn't like to use the word tone).

 @stavros Hatzopoulos, thank you sir for your inputs.

I think there are quite a few distinctions.

I guess both examples can be considered forms of "endaural phenomena" (sounds that are heard without any external acoustic stimulation) although some make a difference considering auditory hallucinations as arising from neurological disorders.

They´re both usually heard only by the sufferer - although some forms of tinnitus have apparently been detected with special equipment and one form is actually called "objective tinnitus" as opposed to subjective which would be all other non-measurable forms.

Yet there isn´t seem to be a consensus about what tinnitus really is or how it happens. Some talk about hair cells damaged, some about psychological distress - so both physical and psychological origins are explored and explanations proposed: either hyperactive neurons compensating the hearing loss associated to ear infections or exposure to loud noise or psychological trauma (or both). Some even argue that tinnitus might be related to spontaneous otoacoustic emissions (which are measurable with sensitive microphones placed in the external ear canal) which most people are unaware of (tinnitus sufferers could be just extremely attuned to such minute sounds). What´s clear is that t´s a potentially very challenging condition (some perceive it as minor while for others is truly catastrophic). 

As for auditory hallucinations, some are a lot more challenging than others. The "exploding head syndrome" for example might not be a problem at all for some if it´s not persistent (I´ve experienced this a few times without massive distress associated, other than the first time maybe); even the "musical ear syndrome" might be actually used creatively by some (mainly composers).

A beautiful account for how much the psychological dimension can affect the subjective experience of sound processing and interpretation (even when physical damage is present beyond repair) is the work of Oliver Sacks "Musicophilia: Tales of Music and the Brain" (see in links below). He delves quite a lot into musical hallucinations and amusia (the inability to discern tone or timbre which which makes music impossible to “hear,” listen to or enjoy) but shares a lot of fascinating insights. 

Then there´s hallucinations as those experienced during mental health challenges (usually considered to arise due to acute stress, sleep deprivation, drug (ab)use, and developmental deficiencies (psychological processes). I believe most psychiatrists probably consider this to be related to the inability to properly internalise one´s inner voice but you´d be better of getting a direct explanation from an expert here. My feeling here is that some mental challenges could be made easier to cope with if strategies were aimed at finding where the wound is, rather than being only based on suppression (however important suppression might be in such cases). We´re all wounded in one or many ways, but  those who suffer this much usually need a lot more work and attention than that usually provided by our medical systems (namely heavy medication and reductionist approaches that tend to encourage shame, debilitating both sufferers and their families).

Please find a couple of links to Youtube videos showing simulations of auditory hallucinations (as in those experienced by mental challenges) and tinnitus.

Hope this helps !

http://www.oliversacks.com/books-by-oliver-sacks/musicophilia/

https://www.youtube.com/watch?v=0vvU-Ajwbok

https://www.youtube.com/watch?v=82Eo9ZfjXbI

Javi Otero

I appreciate your answer

Please see also http://bit.ly/2eJ252H   and  bit.ly/1OHNSKd 

Thank you Sy Fe, I will !

See attached 2 papers, one on musical auditory hallucinations caused by brainstem lesions and a study testing the hypothesis that severity of auditory hallucinations might be related to focal brain shrinkage in perisylvian areas, offering, according to the authors, "strong support for the hypothesis that auditory hallucinations in schizophrenia are indeed related to selective subtle changes in brain morphology."

Anthony, read those papers yourself and see what you make of them. You might get more juice out of them than I could.

http://m.neurology.org/content/44/1/156.short

http://m.cercor.oxfordjournals.org/content/14/1/91.full#ref-21

Now I wonder, can anything purely neurological really exist ?

What makes one disorder “neurological” and another one “mental” ? Is there a clear boundary between them other than in whichever definitions have been accepted ? And... aren´t definitions the map, and not the territory ?

(edited and continued)

Even though both examples can be considered forms of "endaural phenomena" (sounds that are heard without any external acoustic stimulation), some forms of "objective" tinnitus have apparently been detected with special equipment (as opposed to those non-measurable ones that are heard only by the sufferer).

There isn´t seem to be a consensus about what tinnitus really is or how it happens. Whether it is hair cells damaged or psychological distress, both physical and psychological origins have been explored. I believe the main explanation proposed is that of hyperactive neurons compensating the hearing loss associated to ear infections or exposure to loud noise. I´ve also seen people advocating for psychological trauma, and some even argue that tinnitus might be related to spontaneous otoacoustic emissions (which are measurable with sensitive microphones placed in the external ear canal) which most people are unaware of (tinnitus sufferers could be just extremely attuned to such minute sounds). 

What´s clear is that t´s a potentially very challenging condition (some perceive it as minor while for others is truly catastrophic). 

As for non-verbal auditory hallucinations, some are a lot more challenging than others. The "exploding head syndrome" for example might not be a problem at all for some if it´s not persistent (I´ve experienced this a few times without massive distress associated, other than the first time maybe); even the "musical ear syndrome" might be actually used creatively by some (mainly composers). 

Then there´s verbal hallucinations, heard voices that aren´t elaborate or disturbing in content (which according to Sacks, are the majority of cases, occurring in those with no supernatural inclinations or signs of any significant mental illness), and those experienced during mental health challenges (usually considered to arise due to acute stress, sleep deprivation, drug (ab)use, and developmental deficiencies (psychological processes).

For Sacks it seems likely that the "predominantly hostile or persecuting voices of psychosis have a very different basis from the hearing of one's own name called in an empty house; and that this again is different in origin from the voices which come in emergencies or desperate situations". He continues: "Perhaps there is some sort of physiological barrier or inhibition that normally prevents most of us from "hearing" such inner voices as external. Perhaps that barrier is somehow breached or undeveloped in those who do hear constant voices. Perhaps, however, one should invert the question — and ask why most of us do not hear voices. Julian Jaynes, in his influential 1976 book, The Origin of Consciousness in the Breakdown of the Bicameral Mind, speculated that, not so long ago, all humans heard voices — generated internally, from the right hemisphere of the brain, but perceived (by the left hemisphere) as if external, and taken as direct communications from the gods. Sometime around 1000 B.C., Jaynes proposed, with the rise of modern consciousness, the voices became internalized and recognized as our own. Others have proposed that auditory hallucinations may come from an abnormal attention to the subvocal stream which accompanies verbal thinking. It is clear that "hearing voices" and "auditory hallucinations" are terms that cover a variety of different phenomena."

http://www.npr.org/2012/10/24/163271304/exclusive-first-read-hallucinations-by-oliver-sacks

Sorry Anthony I upvoted you from my phone but it somehow crashed on me so will upvote you again

Javi Otero 

"Perhaps there is some sort of physiological barrier or inhibition that normally prevents most of us from "hearing" such inner voices as external. Perhaps that barrier is somehow breached or undeveloped in those who do hear constant voices. Perhaps, however, one should invert the question — and ask why most of us do not hear voices. Julian Jaynes, in his influential 1976 book, The Origin of Consciousness in the Breakdown of the Bicameral Mind, speculated that, not so long ago, all humans heard voices — generated internally, from the right hemisphere of the brain, but perceived (by the left hemisphere) as if external, and taken as direct communications from the gods.”

Perhaps tinnitus is also similar in causation. It is plausible that there is a persistent pre-tinnitus activity (innate evolutionary) that is filtered into awareness as “tinnitus” when there is malfunction of the central executive blocking mechanism (BG -the physiological barrier of Sacks).

Such occurrences have been reported (See Larson PS, Cheung SW: Deep brain stimulation in area LC  controllably triggers auditory phantom percepts.  Neurosurgery 70: 398 – 406, 2012)    and

Larson PS, Cheung SW. A stroke of silence: tinnitus suppression following placement of a deep brain stimulation electrode with infarction in area LC. J Neurosurg. 2013 Jan; 118(1):192-4. PMID: 23082889.)

Most of us is subconscious. What enters our (private) conscious is prioritised (of survival value) - sensations, thoughts/feelings/emotions,? tinnitus  - all filtered from subconscious

Clarification

The basal ganglia (BG) are primarily involved in facilitating “the decision” at any given time; they help to determine which of several possible behaviors the prefrontal cortex (PFC) is to execute. In this sense the BG keep the “non-enabling decisions” out. The BG thus plays a major role in inhibiting behaviour suggested by the “primitive urges”.

The BG is influenced by signals from many parts of the brain, including the prefrontal cortex (PFC), which is involved in prioritisation of the current task goals (and maintaining focus).

The BG have a limbic sector whose components are assigned distinct names: the nucleus accumbens, ventral pallidum, and ventral tegmental area (VTA).

Emotional stimuli dependent on the Darwinian hierarchy for survival gain most priority into this system. In other words, evolutionarily, the brain is always on high alert for perceived threats. Significant neural machinery has thus evolved to ensure survival. Recruitment of this machinery in a particular situation denotes a survival instinct corroboration of that particular situation by the organism. The emotional salience of tinnitus is undoubted.

Volumetric and other imaging techniques confirm the involvement of non auditory areas in the region of the cortico (– prefrontal) –limbic areas. Tinnitus studies report reduction in cortical matter. Similar reduction is reported in addiction studies and is usually interpreted in this circumstance as a reduction of prefrontal control of the limbic areas leading to the excessive “craving” in addiction.

More food for thought

• Is tinnitus similar to addiction craving in some way?

Anthony G Gordon

"I think the causal link is pretty clear in that it is the tinnitus that shrinks and reorganizes parts of the cortex"

"Pretty clear?" What evidence am I missing here  that the rest of the world has?

"There are long term studies showing that poor self-control predisposes to addiction, but surely brain changes could also be secondary to addiction?”

“Poor self control” in neuroscience terms equals diminution of PFC influence and (hence) reduction of PFC matter thus allowing “primitive urges” to overwhelm. These include the “3 Fs” – food, fight and sex. The various addiction “craving” including gambling are provided in the dopamine  repetitively . CBT therapy works in addiction.

Tinnitus is repetitive, imaging shows diminution in PFC, CBT report highest cure rates.  

Anthony G Gordon

In other words you are saying it is not pretty clear?

It is important to consider the following :

1.     Although inferences from correlations assert a predictable relationship between variables, they do not account for it; thus they are less powerful than causal inferences.

2.     Correlations are patterns, occurrences, or changes that vary in relation to each other. Is this variation proven here?

3.     Can the brain activity and/or connectivity signify two or other more different, even opposite things i.e may be even attempts to nullify the tinnitus?

4.     Is tinnitus responsible for the brain activity and/or connectivity rather than the other way around?

5.     Is there a basis for thinking that the relationship is anything other than a mere coincidence?

6.     Could tinnitus itself have multiple causes? Are we looking for one cause only?